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            "title": "Maximum Level Sum of a Binary Tree",
            "titleSlug": "maximum-level-sum-of-a-binary-tree",
            "content": "<p>Given the <code>root</code> of a binary tree, the level of its root is <code>1</code>, the level of its children is <code>2</code>, and so on.</p>\n\n<p>Return the <strong>smallest</strong> level <code>x</code> such that the sum of all the values of nodes at level <code>x</code> is <strong>maximal</strong>.</p>\n\n<p>&nbsp;</p>\n<p><strong>Example 1:</strong></p>\n<img alt=\"\" src=\"https://assets.leetcode.com/uploads/2019/05/03/capture.JPG\" style=\"width: 200px; height: 175px;\" />\n<pre>\n<strong>Input:</strong> root = [1,7,0,7,-8,null,null]\n<strong>Output:</strong> 2\n<strong>Explanation: </strong>\nLevel 1 sum = 1.\nLevel 2 sum = 7 + 0 = 7.\nLevel 3 sum = 7 + -8 = -1.\nSo we return the level with the maximum sum which is level 2.\n</pre>\n\n<p><strong>Example 2:</strong></p>\n\n<pre>\n<strong>Input:</strong> root = [989,null,10250,98693,-89388,null,null,null,-32127]\n<strong>Output:</strong> 2\n</pre>\n\n<p>&nbsp;</p>\n<p><strong>Constraints:</strong></p>\n\n<ul>\n\t<li>The number of nodes in the tree is in the range <code>[1, 10<sup>4</sup>]</code>.</li>\n\t<li><code>-10<sup>5</sup> &lt;= Node.val &lt;= 10<sup>5</sup></code></li>\n</ul>\n",
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            "exampleTestcases": "[1,7,0,7,-8,null,null]\n[989,null,10250,98693,-89388,null,null,null,-32127]",
            "categoryTitle": "Algorithms",
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                    "name": "Tree",
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                    "name": "Depth-First Search",
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                    "name": "Breadth-First Search",
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                    "name": "Binary Tree",
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                    "lang": "C++",
                    "langSlug": "cpp",
                    "code": "/**\n * Definition for a binary tree node.\n * struct TreeNode {\n *     int val;\n *     TreeNode *left;\n *     TreeNode *right;\n *     TreeNode() : val(0), left(nullptr), right(nullptr) {}\n *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}\n *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}\n * };\n */\nclass Solution {\npublic:\n    int maxLevelSum(TreeNode* root) {\n        \n    }\n};",
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                {
                    "lang": "Java",
                    "langSlug": "java",
                    "code": "/**\n * Definition for a binary tree node.\n * public class TreeNode {\n *     int val;\n *     TreeNode left;\n *     TreeNode right;\n *     TreeNode() {}\n *     TreeNode(int val) { this.val = val; }\n *     TreeNode(int val, TreeNode left, TreeNode right) {\n *         this.val = val;\n *         this.left = left;\n *         this.right = right;\n *     }\n * }\n */\nclass Solution {\n    public int maxLevelSum(TreeNode root) {\n        \n    }\n}",
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                {
                    "lang": "Python",
                    "langSlug": "python",
                    "code": "# Definition for a binary tree node.\n# class TreeNode(object):\n#     def __init__(self, val=0, left=None, right=None):\n#         self.val = val\n#         self.left = left\n#         self.right = right\nclass Solution(object):\n    def maxLevelSum(self, root):\n        \"\"\"\n        :type root: TreeNode\n        :rtype: int\n        \"\"\"\n        ",
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                {
                    "lang": "Python3",
                    "langSlug": "python3",
                    "code": "# Definition for a binary tree node.\n# class TreeNode:\n#     def __init__(self, val=0, left=None, right=None):\n#         self.val = val\n#         self.left = left\n#         self.right = right\nclass Solution:\n    def maxLevelSum(self, root: Optional[TreeNode]) -> int:\n        ",
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                {
                    "lang": "C",
                    "langSlug": "c",
                    "code": "/**\n * Definition for a binary tree node.\n * struct TreeNode {\n *     int val;\n *     struct TreeNode *left;\n *     struct TreeNode *right;\n * };\n */\n\n\nint maxLevelSum(struct TreeNode* root){\n\n}",
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                    "lang": "C#",
                    "langSlug": "csharp",
                    "code": "/**\n * Definition for a binary tree node.\n * public class TreeNode {\n *     public int val;\n *     public TreeNode left;\n *     public TreeNode right;\n *     public TreeNode(int val=0, TreeNode left=null, TreeNode right=null) {\n *         this.val = val;\n *         this.left = left;\n *         this.right = right;\n *     }\n * }\n */\npublic class Solution {\n    public int MaxLevelSum(TreeNode root) {\n        \n    }\n}",
                    "__typename": "CodeSnippetNode"
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                {
                    "lang": "JavaScript",
                    "langSlug": "javascript",
                    "code": "/**\n * Definition for a binary tree node.\n * function TreeNode(val, left, right) {\n *     this.val = (val===undefined ? 0 : val)\n *     this.left = (left===undefined ? null : left)\n *     this.right = (right===undefined ? null : right)\n * }\n */\n/**\n * @param {TreeNode} root\n * @return {number}\n */\nvar maxLevelSum = function(root) {\n    \n};",
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                {
                    "lang": "Ruby",
                    "langSlug": "ruby",
                    "code": "# Definition for a binary tree node.\n# class TreeNode\n#     attr_accessor :val, :left, :right\n#     def initialize(val = 0, left = nil, right = nil)\n#         @val = val\n#         @left = left\n#         @right = right\n#     end\n# end\n# @param {TreeNode} root\n# @return {Integer}\ndef max_level_sum(root)\n    \nend",
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                    "lang": "Swift",
                    "langSlug": "swift",
                    "code": "/**\n * Definition for a binary tree node.\n * public class TreeNode {\n *     public var val: Int\n *     public var left: TreeNode?\n *     public var right: TreeNode?\n *     public init() { self.val = 0; self.left = nil; self.right = nil; }\n *     public init(_ val: Int) { self.val = val; self.left = nil; self.right = nil; }\n *     public init(_ val: Int, _ left: TreeNode?, _ right: TreeNode?) {\n *         self.val = val\n *         self.left = left\n *         self.right = right\n *     }\n * }\n */\nclass Solution {\n    func maxLevelSum(_ root: TreeNode?) -> Int {\n        \n    }\n}",
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                {
                    "lang": "Go",
                    "langSlug": "golang",
                    "code": "/**\n * Definition for a binary tree node.\n * type TreeNode struct {\n *     Val int\n *     Left *TreeNode\n *     Right *TreeNode\n * }\n */\nfunc maxLevelSum(root *TreeNode) int {\n    \n}",
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                    "lang": "Scala",
                    "langSlug": "scala",
                    "code": "/**\n * Definition for a binary tree node.\n * class TreeNode(_value: Int = 0, _left: TreeNode = null, _right: TreeNode = null) {\n *   var value: Int = _value\n *   var left: TreeNode = _left\n *   var right: TreeNode = _right\n * }\n */\nobject Solution {\n    def maxLevelSum(root: TreeNode): Int = {\n        \n    }\n}",
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                    "lang": "Kotlin",
                    "langSlug": "kotlin",
                    "code": "/**\n * Example:\n * var ti = TreeNode(5)\n * var v = ti.`val`\n * Definition for a binary tree node.\n * class TreeNode(var `val`: Int) {\n *     var left: TreeNode? = null\n *     var right: TreeNode? = null\n * }\n */\nclass Solution {\n    fun maxLevelSum(root: TreeNode?): Int {\n        \n    }\n}",
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                    "lang": "Rust",
                    "langSlug": "rust",
                    "code": "// Definition for a binary tree node.\n// #[derive(Debug, PartialEq, Eq)]\n// pub struct TreeNode {\n//   pub val: i32,\n//   pub left: Option<Rc<RefCell<TreeNode>>>,\n//   pub right: Option<Rc<RefCell<TreeNode>>>,\n// }\n// \n// impl TreeNode {\n//   #[inline]\n//   pub fn new(val: i32) -> Self {\n//     TreeNode {\n//       val,\n//       left: None,\n//       right: None\n//     }\n//   }\n// }\nuse std::rc::Rc;\nuse std::cell::RefCell;\nimpl Solution {\n    pub fn max_level_sum(root: Option<Rc<RefCell<TreeNode>>>) -> i32 {\n        \n    }\n}",
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                    "lang": "PHP",
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                    "code": "/**\n * Definition for a binary tree node.\n * class TreeNode {\n *     public $val = null;\n *     public $left = null;\n *     public $right = null;\n *     function __construct($val = 0, $left = null, $right = null) {\n *         $this->val = $val;\n *         $this->left = $left;\n *         $this->right = $right;\n *     }\n * }\n */\nclass Solution {\n\n    /**\n     * @param TreeNode $root\n     * @return Integer\n     */\n    function maxLevelSum($root) {\n        \n    }\n}",
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                    "lang": "TypeScript",
                    "langSlug": "typescript",
                    "code": "/**\n * Definition for a binary tree node.\n * class TreeNode {\n *     val: number\n *     left: TreeNode | null\n *     right: TreeNode | null\n *     constructor(val?: number, left?: TreeNode | null, right?: TreeNode | null) {\n *         this.val = (val===undefined ? 0 : val)\n *         this.left = (left===undefined ? null : left)\n *         this.right = (right===undefined ? null : right)\n *     }\n * }\n */\n\nfunction maxLevelSum(root: TreeNode | null): number {\n\n};",
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                {
                    "lang": "Racket",
                    "langSlug": "racket",
                    "code": "; Definition for a binary tree node.\n#|\n\n; val : integer?\n; left : (or/c tree-node? #f)\n; right : (or/c tree-node? #f)\n(struct tree-node\n  (val left right) #:mutable #:transparent)\n\n; constructor\n(define (make-tree-node [val 0])\n  (tree-node val #f #f))\n\n|#\n\n(define/contract (max-level-sum root)\n  (-> (or/c tree-node? #f) exact-integer?)\n\n  )",
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                {
                    "lang": "Erlang",
                    "langSlug": "erlang",
                    "code": "%% Definition for a binary tree node.\n%%\n%% -record(tree_node, {val = 0 :: integer(),\n%%                     left = null  :: 'null' | #tree_node{},\n%%                     right = null :: 'null' | #tree_node{}}).\n\n-spec max_level_sum(Root :: #tree_node{} | null) -> integer().\nmax_level_sum(Root) ->\n  .",
                    "__typename": "CodeSnippetNode"
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                    "lang": "Elixir",
                    "langSlug": "elixir",
                    "code": "# Definition for a binary tree node.\n#\n# defmodule TreeNode do\n#   @type t :: %__MODULE__{\n#           val: integer,\n#           left: TreeNode.t() | nil,\n#           right: TreeNode.t() | nil\n#         }\n#   defstruct val: 0, left: nil, right: nil\n# end\n\ndefmodule Solution do\n  @spec max_level_sum(root :: TreeNode.t | nil) :: integer\n  def max_level_sum(root) do\n\n  end\nend",
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            "hints": [
                "Calculate the sum for each level then find the level with the maximum sum.",
                "How can you traverse the tree ?",
                "How can you sum up the values for every level ?",
                "Use DFS or BFS to traverse the tree keeping the level of each node, and sum up those values with a map or a frequency array."
            ],
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